Wired radio communication system



Jan. 23, 1934. w DUBIUER 1,944,226

WIRED RADIO COMMUNICATION SYSTEM Original Filed May 11, 1925 2Sheets-Sheet 1 I gwwcmioz mow MI, 351 flu wow,

Jan. 23, 1934. w. DUBILIER WIRED RADIO COMMUNICATION SYSTEM 2SheetsSheet 2 Original Filed May 11, 1923 LUCK L R F. m B U Y RD M m RNM m Wm T mm A W Y B Patented Jan. 23, 1934 UNITED STATES WIRED RADIOCOMMUNICATION SYSTEM William Dubilier, New

Rochelle, N. Y., assignor to Radio Patents Corporation, New York, N. Y.,

a corporation of New York Application May 11, 1923, Serial No. 638,167Renewed September 30, 1933 6 Claims.

This invention relates to improvements in methods of communicationwherein currents of high or radio frequency are employed and has for itsobject the provision of means for effectively controlling suchcommunication in cases where conductors, such as for example, the wiresof a domestic electric lighting system, are utilized for receptionpurposes.

The invention is primarily intended to be applied to cases wherecommunication is to be established by the aid of the so-called wiredwireless system, that is to say, in cases where currents of high orradio frequency are transmitted along conductors or wires.

According to the invention means are provided whereby high frequencycurrents or currents of radio frequency may be excluded from or admittedto conductors, such as for example, the wires of a domestic electriclighting system, either wholly or in part for the purpose above setforth.

Further features of the invention will hereinafter appear.

In transmitting high frequency currents for signalling or similarpurposes over the wires of an ordinary electric lighting system, it issomewhat difficult, especially when the system is provided with a largenumber of branches, to control the use of these currents without at thesame time interfering with the use of the commercial currents on suchwires.

With the present invention this difficulty is overcome by inserting aset of inductances and capacities on the different branch-offs. In thismanner it is possible to control the high frequency currents for eachbranch without materially affecting the other branches and withoutmaterially interfering with the ordinary commercial or lightingcurrents. Thus the present invention renders possible the provision of asystem of transmitting ordinary currents and high frequency currentsover the same set of wires and the control of one independent of theother.

In the ordinary electric lighting system electric meters are usuallyinstalled either in the different branch-offs or in the main supplycircuit and the inductances in such meters may sometimes interfere withthe high frequency cur-' rents. This can be overcome by shunting acondenser across the meter coil to form a short cir-- cuit or an easypath for the high frequency currents without materially affecting thecommercial currents. A condenser arranged in this manner will also, ofcourse, eliminate any possible dangerous effects that the high frequencycurrents would be likely to have upon the meter coils.

Similarly when the electric lighting supply is by means of alternatingcurrent, and a transformer is included in the main supply circuit or inthe branch-offs, a condenser or condensers maybe shunted across betweenthe output and input Wires of the transformer in order to provide aneasy path for the high frequency currents. 6

Figure 1 shows a lighting or power circuit with apparatus according tomy invention connected thereto. Figure 2 shows another form of myinvention and Figure 3 indicates how the apparatus for utilizing radiofrequency currents 7 can be controlled so as to prevent unauthorizedpersons from obtaining the benefit thereof.

Referring now to the accompanying drawings, Figure 1 illustratesdiagrammatically, by way of example, one convenient mode of carrying theinvention into effect as applied to the commercial electric lightingsystem of a building in which there are a pair of main supply lines anda plurality of branches leading therefrom. The invention may be appliedto the pair of main lines so alone or to one or more of the branch linesor, if desired, to the main lines and to one or more of the branches. InFigure 1 for the sake of illustration there are shown three branches B,B and B and since the invention may take the same form whether it beapplied to a main or to a branch line, it will only be necessary tofully describe the embodiment illustrated as applied, say to the branchline B.

Referring now to the branch line B in detail, D represents an inductanceor impedance arranged in series with the lines and CC represents a pairof condensers connected across the lines with the centre point grounded.Of course, it will be appreciated that only one or any desired number ofcondensers may be employed and and that in cases where one side of theline is already grounded it will only be necessary to arrange aninductance in series with and one or more condensers across the lines.

In connecting an inductance or impedance in series with the line, it maybe found in certain circumstances that the said inductances or impedanceintroduces into circuit a resistance sufficiently great to causeconsiderable losses to occur in respect of the commercial current and toproduce a heating up of the coils resulting in further seriousobjections. In order to reduce these losses and the heating up of thecoils to a minimum, the inductances or impedance is made up of a fewturns only and is magnetically coupled to another inductance, which maybe termed a secondary inductance, of many turns, and a condenser isconnected across the ends of the said secondary inductance. In Figure 1the secondary inductance is denoted by E and the condenser associatedwith same is denoted by F. Ihis secondary circuit, containing thesecondary inductance and a condenser, is adjusted so that it has anatural period or frequency which is the same or about the same as thatof the high frequency current which it is desired to control.

The main lines and one or more of the branch lines are preferablyprovided with means whereby the inductances can be short-circuited andcut out of the line, or a complete high frequency circuit may beconnected or disconnected, or the condenser or condensers may beconnected or disconnected either by blocking or switching. It is alsopreferred that these means should be enclosed or encased in a suitablecontainer. indicated in Figure l by dotted lines H, which may be sealedin any desired manner, such as by lock and key, so that only authorizedpersons may be permitted to examine or tamper with such means and theinterior of said container.

In order that the high frequency currents may be placed under perfectcontrol and that the persons desirous of using these currents may onlybe permitted to do so upon the payment of a predetermined fee or charge,the above mentioned container may be provided with a timing deviceoperated by any known and suitable form of coin-freed mechanism, suchas, for example, a clockwork mechanism having a coin in a slot controlas is commonly employed in meters of other lLnds. In this manner it ispossible to control the high frequency currents in such a manner thatwhen a coin is inserted in the meter or container the inductances orcapacities or both are cut out of circuit and the high frequencycurrents are thus permitted to be employed, for a given predeterminedperiod of time.

Figure 3 shows more fully how the use of the radio frequency currentscan be controlled. In this view, the casing H, as shown, is providedwith a lock indicated diagrammatically at L, so that only the personhaving the proper key can obtain access to the inside of the casing H toadjust the apparatus in the manner required for purposes of radioreception. Further the two condensers C, which are bridged across themain line wires W are shown as having in the conductors lead thereto,circuit breaking switches S and the inductances D also have shortcircuiting switches S. The two sets of switches, S and S are indicatedas being connected to means such as a suitable coin-controlled deviceVI, having a slot A, so that unless a coin is deposited in this device,the switches will maintain the position which they occupy in Figure 3,then, on the deposit of a coin the device M, if this device beassociated with suitable timing mechanism, messages can be received fora predetermined period; after which the device operates in such a manneras to open again the switches S and close the switches S. It is, ofcourse, understood that the device M and connections therefrom to theswitches S and S are indicated only in a diagrammatic way in Figure 3.

If desired, a plurality of sets of high frequency currents may beimposed upon the same electric conductors or wiring. In thesecircumstances a plurality of sets of coils and condensers are in stalledin the circuit or branch, the number of such sets corresponding with thenumber of sets of high frequency currents which it is desired tocontrol, and each set of coils and condensers is tuned to the same orabout the same frequency as that of the particular high frequencycurrent to be controlled. Preferably the plurality of sets of coils andcondensers are enclosed in a single container which is divided into aplurality of compartments and each compartment is adapted to contain oneof the said sets. Furthermore, it is also preferred to provide eachcompartment with a suitable form of sealing means, such as a lock andkey, and also with an individual coinfreed mechanism for the separatecontrol of the cutting out or switching means associated with the set ofapparatus enclosed in that particular compartment.

In Figure 2 of the accompanying drawings there is shown, as an example,an arrangement of inductances and capacities suitable for thecontrolling of two sets of high frequency currents, the parts whichcorrespond with those employed with th arrangement shown in Figure 1being denoted by the same reference letters as those which are assignedto such parts in Figure l.

The manner in which the casing in Figure 2 can be divided up intocompartments and each compartment provided with separate looks or coincontrolled devices or both, will be obvious especially in view of thearrangement of Figure 3.

While the present invention has been described more particularly asapplied to conductors such as those employed in an ordinary commercialelectric lighting system, it is to be understood and of course it willbe readily appreciated that the invention is equally applicable to theconductors or wires of telephone or power circuits.

Having now particularly described and ascertained the nature of my saidinvention and in what manner the same is to be performed, I declare thatwhat I claim is:

I. In a composite system, a conductor carrying a power supply and highfrequency currents superimposed thereon, means comprising a transformer,the primary of which is made up of comparatively few turns of negligibleimpedance to power currents and the secondary of which is connected incircuit with a condenser and tuned to the high frequency, one end ofsaid means being connected to said conductor, a load connected to theother end of said means operated by the power supply, a receiver for thereception of the high frequency signals also connected to the other endof said means and means for shunting said first means to permit saidsignalling currents to operate said receiver.

2. In a composite system, main and branch conductors carrying a powersupply and a plurality of high frequency currents superimposed thereon,a plurality of impedance means in each branch conductor, each of saidimpedance means offering a negligible impedance to said power currentsand each offering a high impedance to a specific one of said highsignalling frequencies, a load for each branch conductor operated bysaid power supply, receiver apparatus for each branch conductor for thereception of said plurality of high frequencies, said plurality ofimpedance means being interposed between said receiver apparatus andload on each branch on the one side and the main conductor on the otherside and means for selectively shunting one of said impedance meanswhereby the corresponding high frequency currents operate the associatedreceiver.

3. In a wired wireless composite signalling system, a conductor carryingpower currents and high frequency currents superimposed thereon, animpedance offering a negligible impedance to said power currents and ahigh impedance to the high frequency currents, and comprising inductanceand capacity, said high impedance being connected in series with saidconductor, one end of said impedance being connected to said conductor,a load connected to the other end of said impedance operated by thepower supply, a receiver for the reception of its high frequency signalsalso connected to the other end of said impedance, said impedancenormally constituting the sole electrical path from said line to saidreceiver and load, and means for shunting said first impedance toprovide an electrical path for said signalling currents to operate saidreceiver.

4. In a wired wireless composite signalling system, a conductor carryingpower currents and high frequency currents superimposed thereon, aplurality of branch conductors, means offering a negligible impedance tosaid power currents and a high impedance to the high frequency currentsand comprising inductance and capacity, said high impedance beingconnected in series with each of said branch conductors, one end of eachof said impedances being connected to said branch conductors, a loadconnected to the other end of each of said impedances operated by thepower supply, a receiver for the reception of the high frequency signalsalso connected to the other end of each of said impedances, saidimpedances normally constituting the sole electrical paths from saidline to each of said receivers and loads, and

individual means for shunting each of said first impedances to provideelectrical paths for said signalling currents to operate said receivers.

5. In a wired wireless composite signalling system; a conductor carryingpower currents and high frequency currents superimposed thereon, meansoffering a negligible impedance to said power currents and a highimpedance to said signalling currents, one end of said means beingconnected to said conductor, a load connected to the other end of saidmeans operated by the power supply, a receiver for the reception of highfrequency signals also connected to the other end of said means, saidmeans normally constituting the sole conductor path from said line tosaid receiver, and means for disabling said first means to provideelectrical paths for said signalling currents to operate said receiver.

6. In a wired wireless composite signalling system, a conductor carryingpower currents and high frequency currents superimposed thereon, aplurality of branch conductors extending from said main conductor, meansindividual to each of said branch conductors offering negligibleimpedance to said power currents and a high impedance to said signallingcurrents, one end of each of said means being connected to itsindividual branch conductors, loads connected to the other end of saidmeans operated by the power supply, receivers for the reception of highfrequency signalsalso connected to the other end of each of said means,said means normally constituting the sole electrical paths from saidline to said receivers, and means for disabling said first means topermit said signalling currents to operate said receivers.

WILLIAM DUBILIER.

